While congestive heart failure in Diabetes Mellitus is common, its explanation on the basis of obstructive large or small coronary vessel disease is inadequate. We propose to explore the presence of a diabetic carciomyopathy in experimentally induced diabetes, and determine its relation to hyperglycemia and its control. Myocardial mechanics will be explored in vitro in papillary muscles to determine contractility changes, catecholamine responsiveness, alterations of relaxation processes, and compliance alterations. Pathology and histopathology will be studied relative to connective tissue alterations, glycoprotein infiltration, subcellular integrity and small vessel pathology. Adequacy of large and small vessel coronary blood flow will also be assessed in vivo. These studies should establish whether there is a true Diabetic Cardiomyopathy, its characteristics and relation to therapy.